At the present time, plasmas are difficult to contain and utilize. One notable use of plasmas utilizing particles of opposite charge is in fusion reactors wherein the dual-charged plasma is raised to high energy levels and contained within strong magnetic fields. The dual-charged plasma is amorphous in shape in that it is contained as a ring shaped mass held in place by magnetic fields and includes particles of unlike charge having pathways or orbits within the ring that are not precisely fixed or defined.
Plasmas with a single sign of charge have been previously studied. (See, e.g., "Non-Neutral Plasma Physics" (C. W. Roberson and C. F. Driscoll, ed.), AIP Conference Proceedings 175, Am. Inst. Physics, New York (1988).) These plasmas are known by several different names such as "nonneutral plasmas" or "single component plasmas." In nonneutral plasma research, studies are conducted in a regime of very stable plasmas with low speed energy per particle and low to modest plasma densities.
The main thrust of the studies of nonneutral plasmas is to achieve long term confinement of the plasmas and to study such properties as wave phenomena. In order to achieve long term confinement, these plasmas are stored in traps, such as the Penning trap, and are cooled to cryogenic temperatures. The free energy stored in these plasmas is minimized. The available energy per particle is typically about one electron volt or less. Typical densities studied are about 10.sup.13 m.sup.-3 for conventional magnetic fields of about 700 Gauss or up to 4.times.10.sup.16 m.sup.-3 for high magnetic fields such as 80 kGauss (8 Teslas). These plasmas have very low ratios of plasma frequency to the cyclotron frequency. The relatively low density of these plasmas and their low stored energy per particle indicate that the total stored energy per unit volume, which is the product of the number of particles per unit volume times the energy per particle, is very low.
A traditional use of nonneutral plasmas is in particle accelerators such as cyclotrons where charged particles are raised to high energy levels and contained by complex magnets. The shape of the mass of charged particles is essentially amorphous. A third use of charged particles is for electron beams. These beams are useful for welding and deposition, but are transient in nature and of a simple, line geometry.